1. Field of the Invention
The present invention relates generally to integrated circuit devices, and more specifically to high impedance load devices.
2. Description of the Prior Art
CMOS static random access memory (SRAM) are increasingly used in the electronics industry due to their combination of speed, low power, and no requirements for refresh. A CMOS SRAM cell is built around a cross-coupled latch and accessed, typically, by two control gates for a standard SRAM cell. The basic SRAM cell may be formed using cross-coupled CMOS inverters, each having two n-channel and p-channel transistors. The p-channel transistors often are replaced with resistive loads. Typical loads presently used include a polycrystalline silicon resistor or a pn junction formed by two back-to-back polycrystalline silicon diodes. These types of resistive loads still take up large amounts of physical layout space.
With the desire to increase the density of integrated circuit devices on silicon, it would be desirable to decrease the physical layout space required by resistive loads such as polycrystalline silicon resistors and p-n junctions. Therefore, it would be desirable to provide a highly resistive polycrystalline resistive structure that requires less physical layout space than the presently used resistive load devices.